Field of the Invention
Embodiments of the present invention relate to testing a solenoid of a directional control valve in a subsea hydrocarbon production control system.
Description of Prior Art
Continuously energized electro-hydraulic, solenoid operated directional control valves (DCVs) are often used in subsea well electro-hydraulic production control systems in safety related or safety critical applications where loss of electrical power, or the detection of a dangerous condition, results in the de-energizing of a coil of the DCV solenoid and the resultant closure, and hydraulic pressure venting, of the hydraulic supply. Under these conditions, it is therefore critical that an armature of the DCV solenoid not stick in the open position after the solenoid coil is de-energized. However, since such continuously energized valves are often energized for extended periods of time, it cannot be guaranteed that the armature of a DCV solenoid will move to close the valve when demanded to do so by de-energizing the solenoid coil.